An updated version of CentOS Atomic Host (tree version 7.20170209), is now available, including significant updates to docker (version 1.12.5), kubernetes (version 1.4) and etcd (version 3.0.15).

CentOS Atomic Host is a lean operating system designed to run Docker containers, built from standard CentOS 7 RPMs, and tracking the component versions included in Red Hat Enterprise Linux Atomic Host.

CentOS Atomic Host is available as a VirtualBox or libvirt-formatted Vagrant box, or as an installable ISO, qcow2 or Amazon Machine image. These images are available for download at cloud.centos.org. The backing ostree repo is published to mirror.centos.org.

CentOS Atomic Host includes these core component versions:

• atomic-1.14.1-5.el7.x86_64
• cloud-init-0.7.5-10.el7.centos.1.x86_64
• docker-1.12.5-14.el7.centos.x86_64
• etcd-3.0.15-1.el7.x86_64
• flannel-0.5.5-2.el7.x86_64
• kernel-3.10.0-514.6.1.el7.x86_64
• kubernetes-node-1.4.0-0.1.git87d9d8d.el7.x86_64
• ostree-2016.15-1.atomic.el7.x86_64
• rpm-ostree-client-2016.13-1.atomic.el7.x86_64

Containerized kubernetes-master

The downstream release of CentOS Atomic Host ships without the kubernetes-master package built into the image. Instead, you can run the master kubernetes components (apiserver, scheduler, and controller-manager) in containers, managed via systemd, using the service files and instructions on the CentOS wiki. The containers referenced in these systemd service files are built in and hosted from the CentOS Community Container Pipeline, based on Dockerfiles from
the CentOS-Dockerfiles repository.

These containers have been tested with the kubernetes ansible scripts provided in the upstream contrib repository, and they work as expected, provided you first copy the service files onto your master.

Upgrading

If you're running a previous version of CentOS Atomic Host, you can upgrade to the current image by running the following command:

$ sudo atomic host upgrade

Images

Vagrant

CentOS-Atomic-Host-7-Vagrant-Libvirt.box and CentOS-Atomic-Host-7-Vagrant-Virtualbox.box are Vagrant boxes for Libvirt and Virtualbox providers.

The easiest way to consume these images is via the Atlas / Vagrant Cloud setup (see https://atlas.hashicorp.com/centos/boxes/atomic-host). For example, getting the VirtualBox instance up would involve running the following two commands on a machine with vagrant installed:

$ vagrant init centos/atomic-host && vagrant up --provider virtualbox 

ISO

The installer ISO can be used via regular install methods (PXE, CD, USB image, etc.) and uses the Anaconda installer to deliver the CentOS Atomic Host. This image allows users to control the install using kickstarts and to define custom storage, networking and user accounts. This is the recommended option for getting CentOS Atomic Host onto bare metal machines, or for generating your own image sets for custom environments.

QCOW2

The CentOS-Atomic-Host-7-GenericCloud.qcow2 image is suitable for use in on-premise and local virtualized environments. We test this on OpenStack, AWS and local Libvirt installs. If your virtualization platform does not provide its own cloud-init metadata source, you can create your own NoCloud iso image.

Amazon Machine Images

SHA Sums

6f8b91373c763cf96ffead6ca044ddf6eea5c0b102a239933c112a7f1089396e  CentOS-Atomic-Host-7.1701-GenericCloud.qcow2
380dcbdd4514f87f8915fee418cc965985c89a91b9182af622e36ffad26c9e04  CentOS-Atomic-Host-7.1701-GenericCloud.qcow2.gz
0bf3d5ec95d40cee94bc80e7c19206b3a260d2835fa43f1e99965bb8f99a777d  CentOS-Atomic-Host-7.1701-GenericCloud.qcow2.xz
bc55326e54832e3e08530e41cb738c4b293a7645c960a4c9be7f66024770a68c  CentOS-Atomic-Host-7.1701-Installer.iso
aaba6ca5e3b0a64abff843bff28eb82092e39fe82f120c76614822334ff22462  CentOS-Atomic-Host-7.1701-Vagrant-Libvirt.box
8d3c64895a40638cb8659186a0caabef9fc10ba944a130eda53f7d2109cfba35  CentOS-Atomic-Host-7.1701-Vagrant-VirtualBox.box

Release Cycle

The CentOS Atomic Host image follows the upstream Red Hat Enterprise Linux Atomic Host cadence. After sources are released, they're rebuilt and included in new images. After the images are tested by the SIG and deemed ready, we announce them.

Getting Involved

CentOS Atomic Host is produced by the CentOS Atomic SIG, based on upstream work from Project Atomic. If you'd like to work on testing images, help with packaging, documentation -- join us!

The SIG meets weekly on Thursdays at 16:00 UTC in the #centos-devel channel, and you'll often find us in #atomic and/or #centos-devel if you have questions. You can also join the atomic-devel mailing list if you'd like to discuss the direction of Project Atomic, its components, or have other questions.

Getting Help

If you run into any problems with the images or components, feel free to ask on the centos-devel mailing list.

Have questions about using Atomic? See the atomic mailing list or find us in the #atomic channel on Freenode.